1. Field of the Invention
This invention relates to ligament anchor systems and devices for use in arthroscopic surgical procedures involving securing an end of a ligament, such as the anterior cruciate ligament, stint, or the like, under tension within a bone mass.
2. Prior Art
In certain ligament replacement surgical procedures, particularly arthroscopic knee surgery, involving a cruciate ligament replacement, it is usual to form a tunnel through bone masses on both sides of a joint for installing a ligament therein. Such installation has generally involved fitting the ligament through the prepared tunnel and attaching its ends onto the bone cortex surfaces as with staples, or the like, for maintaining the ligament under tension across the joint. Examples of arrangements for attaching ligament ends within a bone mass are shown in a United Kingdom patent, No. G.B. 2,084,468A; and a patent of the present inventors, U.S. Pat. No. 4,772,286. A U.S. patent application of the present inventors, application Ser. No. 235,194, entitled "Channel Ligament Clamp and System", shows a device for securing a ligament end onto a bone mass. Additionally, another earlier patent of the present inventors, U.S. Pat. No. 4,870,957, entitled "Ligament Anchor System", shows a stud for mounting a ligament end within a ligament tunnel that involves a threaded sleeve or footing that is turned into a tapped endosteal bone. Another U.S. patent application of the present inventors, application Ser. No. 352,153, entitled "Interference Screw, System and Process", provides an interference screw and system for turning it into a ligament tunnel, alongside a ligament end therein.
All of the above-cited devices and systems involve hardware and systems for connection of a ligament to the endosteal portion of the distal femur, and the "Ligament Anchor System" application involves a separate stud and footing for mounting a ligament end to bone. Whereas, the present invention employs a single stud only that is for insertion to closely fit in a ligament tunnel and to lock into the cortex surface, and is arranged for mounting a ligament end to a rear end thereof. The stud of the present invention is for sliding along the prepared ligament tunnel. The stud forward end sections are split by a slot, allowing the section to be squeezed together as the stud is urged into the tunnel. The stud forward end, as it emerges from a cortex end of the ligament tunnel, flexes outwardly, a hook end section of the stud to extend beyond the tunnel edge. Which hook edge thereby binds into the surrounding bone mass or over the outer cortex when the stud is pulled back into the ligament tunnel, securely and permanently mounting that stud end to that bone cortex.